Alcohol-Specific Computerized Interventions to Alter Cognitive Biases: A Systematic Review of Effects on Experimental Tasks, Drinking Behavior, and Neuronal Activation

Abstract

Background: In patients with alcohol use disorder, novel interventions to increase abstinence have attracted growing attention. Interventions aimed at modifying cognitive biases linked to alcohol use [i.e. cognitive bias modification (CBM)] may serve as an add-on to standard therapy. This systematic review thoroughly aggregates existing data on the effects of three alcohol-specific computerized interventions, namely attentional bias modification (AtBM), approach bias modification (ApBM), and inhibition training (IT). In doing so, each CBM's effects on experimental tasks assessing the relevant biases, drinking behavior, and neurophysiology are summarized. Also, the influence of drinking behavior severity and motivation to change drinking behavior are discussed. Methods: A literature search was conducted in four databases for original research articles published between 2000 and May 2019. Studies were eligible if investigating the effects of alcohol-specific computerized interventions (AtBM, ApBM, IT) on drinking behavior, bias change, and/or neurophysiology. Forty eligible articles were classified as being either a non-clinical experimental lab study (ELS) or clinical randomized-controlled trial (RCT) and summarized. Results: While AtBM seems to influence attentional bias, its effects on drinking behavior are inconsistent. As for ApBM, the best effects on drinking behavior are obtained in clinical samples. Effects of ApBM on approach bias are mixed. Interestingly, those clinical RCTs which investigated ApBM effects on bias change as well as on drinking outcome, reported consistent effects in both measures (i.e. either effects on bias and drinking or no effects). Studies on IT are limited to non-clinical samples and show inconsistent effects on drinking behavior. Considering ITs effects on implicit semantic associations, most studies do not support the conceptualization of IT as a form of memory bias modification, while reports on IT's effects on inhibitory control are still incomplete. Conclusions about the overall influence of drinking behavior severity are hampered by the non-uniform use of sample descriptions. Conclusions: In clinical samples, ApBM has shown more consistent beneficial effects, while evidence on AtBM is more inconsistent, and data on IT still lacks important information. Conclusions about the influence of drinking behavior severity would be facilitated by a uniform use of clearly defined sample descriptions.

Keywords: alcohol use disorder; alcohol-specific computerized intervention; approach bias; attentional bias; cognitive bias modification; inhibition.

Figure 1

PRISMA flow chart of the conducted literature search.

Figure 2

Alignment of studies according to CBM type (AtBM, ApBM, or IT) and study type [non-clinical experimental laboratory study (ELS) or clinical randomized-controlled trial (RCT)] and overview of effects on bias change/experimental tasks as well as proximal and distal drinking outcomes. Notes. This figure is organized according to CBM type [i.e. Attentional bias modification (AtBM), approach bias modification (ApBM) and inhibition training (IT)] and within the CBMs differentiated between experimental laboratory study (ELS) including non-clinical samples and randomized-controlled trials (RCT) including clinical samples. Effects are reported as follows, with color coding in parentheses: + significant effect (green); (+) trend (green); +/− mixed results (orange); − no effect of the intervention (red); (−) no effects in ITT analysis, but subgroup with bias change showed drinking reduction (red); * outcome assessed, but not statistically tested or no control group (white); (*) no clear effect of intervention, but pre-post reduction in all groups (including control group) (white); Ǿ not measured (gray). Effects are summarized using a conservative approach in the spirit of intention-to-treat analyses (whole group analyses) and only positive effects observed against a control group were seen as clear evidence. Proximal effects: up to 1 month; Distal effects: 1 month and more. AAT, Approach Avoidance Task; ApBM, Approach Bias Modification; AtBM, Attentional Bias Modification; AUD, Patients With Alcohol Use Disorders; CBM, Cognitive Bias Modification; ELS, Experimental Laboratory Study; GNG, Go/Nogo Task; HD, Heavy Drinkers; HFD, Harmful Drinkers; HZD, Hazardous Drinkers; IAT, Implicit Association Task; IT, Inhibition Training; RCT, Randomized-Controlled Trial; SD, Social Drinkers; SRC, Stimulus Response Compatibility Task; SST, Stop-Signal Task; TT, Taste Test; VPT, Visual Probe Task. Reading example: In those RCTs on ApBM, which measured both, bias change and drinking effects (–28), one can see that the effects on bias change (column “bias change”) consistently point in the same (positive) direction as the effects on proximal and distal drinking outcomes. In the ELS studies on ApBM, not only is this pattern less clear, but one can also see that two-thirds of the studies failed to report a bias change in the first place.

Figure 3

Alignment of all studies according to description of the samples’ severity of drinking behavior and overview of effects on experimental tasks and proximal and distal drinking outcomes. Notes. Effects are reported as follows, with color coding in parentheses: + significant effect (green); (+) trend (green); +/− mixed results (orange); − no effect of the intervention (red); (−) no effects in ITT analysis, but subgroup with bias change showed drinking reduction (red); * outcome assessed, but not statistically tested or no control group (white); (*) no clear effect of intervention, but pre-post reduction in all groups (including control group) (white); Ǿ not measured (gray). Effects were summarized using a conservative approach in the spirit of intention-to-treat analyses (whole group analyses) and only positive effects observed against a control group were seen as clear evidence. Proximal effects: up to 1 month; Distal effects: 1 month and more. AAT, approach avoidance task; ApBM, Approach bias modification; AtBM, Attentional bias modification; AUD, patients with alcohol use disorders; CBM, cognitive bias modification; ELS, experimental laboratory study; GNG, Go/NoGo task; HD, heavy drinkers; HFD, harmful drinkers; HZD, hazardous drinkers; IAT, implicit association task; IT, inhibition training; RCT, randomized-controlled trial; SD, social drinkers; SRC, Stimulus response compatibility task; SST, stop-signal task; TT, taste test; VPT, visual probe task. Reading example: In the RCTs summarized in the lower part of the figure, one can see that the effects on bias change (column “bias change”) mostly point in the same direction as the effects on proximal and distal drinking outcomes. In the ELS studies, this pattern is inconsistent.

Figure 4

Alignment of studies according to AUDIT means and overview of proximal and distal drinking outcomes. Notes. Columns show if study yielded significant effect, indicating that the intervention reduced drinking behavior or relapse rates. Effects are reported as follows + significant effect; (+) trend; +/− mixed results (if different measures were reported); − no effect of the intervention; (−) no effects in ITT analysis, but subgroup with bias change showed drinking reduction; * outcome assessed, but not statistically tested or no control group; (*) no clear effect of intervention, but pre-post reduction in all groups (including control group); Ǿ not measured. Effects were summarized using a conservative approach in the spirit of intention-to-treat analyses (whole group analyses) and only positive effects observed against a control group were seen as clear evidence. Proximal effects: up to 1 month; Distal effects: 1 month and more. Top row: WHO terminology to categorize drinking behavior according to scored AUDIT values: non-problematic: AUDIT 0–7; hazardous: AUDIT 8–15; harmful: AUDIT 16–19; probability of dependence: AUDIT > 20. If not stated in the original research paper, pooled means and standard deviations of AUDIT values were calculated. RR, Relapse rate; TT, Taste test, WHO, World Health Organization.